The invention relates to an optical reader for reading a color image on a document or paper.
A variety of arrangements are proposed in the prior art to provide an optical reader which reads a color image on a paper. For example, Japanese Laid-Open Patent Application No. 162,570/1982 discloses an optical reader including three light emitting elements which emit light of three primary colors respectively, a single lens which transmits the light from the three color light emitting elements to a paper, a light receiving element for receiving reflected light from the paper surface, and a binary digitizing circuit for digitizing an output from the light receiving element into a binary value.
The three primary color emitting elements are energized in a sequential manner, and the light from these elements are transmitted through the lens to illuminate a paper. The reflected light impinges upon the light receiving element, separately for the light from the individual light emitting elements. The binary digitizing circuit determines an output from the light receiving element separately for each color, and the optical reader reads a color image on the paper on the basis of such result of determination. However, in the disclosed apparatus, each light emitting element can be independently adjusted as to an amount of light emitted therefrom, but the specific technique of adjustment is not disclosed.
A plurality of arrangements are available to construct an optical reader which incorporate optical fibers. However, there is no optical reader which is constructed to transmit light from three light emitting elements, which emit light of three primary colors, to the surface of a paper through a single optical fiber.